chrisk
Hero member
- Location
- Brisbane, Australia
Nod, not knob 
880SFC Dyno results
- Thread starter chrisk
- Start date
Chris,
Far more important and useful than a set of jet drills, is a jet guage. Dellorto jets are not as consistant as one might wish, especially when fine-tuning. I've come across huge discrepancies, perhaps jets from different manufacturing batches.
Mark also has a point re Guzzi carbs. I remember changing out the emulsion tubes on the first set of 36 PHB I did for my triple, these were kindly donated by a Guzzi owner. I never ran the bike with the original Guzzi tubes, so cannot comment on the effects these may have, just noticed the difference and swapped them.
piet
Far more important and useful than a set of jet drills, is a jet guage. Dellorto jets are not as consistant as one might wish, especially when fine-tuning. I've come across huge discrepancies, perhaps jets from different manufacturing batches.
Mark also has a point re Guzzi carbs. I remember changing out the emulsion tubes on the first set of 36 PHB I did for my triple, these were kindly donated by a Guzzi owner. I never ran the bike with the original Guzzi tubes, so cannot comment on the effects these may have, just noticed the difference and swapped them.
piet
chrisk
Hero member
- Location
- Brisbane, Australia
I've squirted carby cleaner up every orifice and back, and compressed air .... all galleries are free.
Checked my 68 pilot jets and a .0.65 drill fits freely, but a 0.70 doesn't. Poor mans jet gauge
At this stage I await the new short tip mixture screws, and choke plungers with rubber ends. Chuck it all together and see what happens.
Checked my 68 pilot jets and a .0.65 drill fits freely, but a 0.70 doesn't. Poor mans jet gauge
At this stage I await the new short tip mixture screws, and choke plungers with rubber ends. Chuck it all together and see what happens.
markQLD
Hero member
- Location
- QLD Australia
ay Chris, re my call today:
this is your other 'oil leak' thread about the fitted atomizer sizes, that was starting to do my head in ???
I understand the early reply, as the carbs probably were set up for a Guzzi. maybe SP3 948cc?
but then you start to lose me here?
and now you say AB 256 fitted? A simple mix up? (dunno)
My question is,
Have you replaced the AB 256?/265 atomizer with AB 260?
And it's worth reading your earlier 'oil leak' thread again, as there is good advice from Q and Lee in that thread, and the Piranha Brothers know far more about setting up SF twins than this bloke from da cane fields.
http://www.laverdaforum.com/forum/index.php/topic,97735.0.html
just saying 8)
this is your other 'oil leak' thread about the fitted atomizer sizes, that was starting to do my head in ???
I understand the early reply, as the carbs probably were set up for a Guzzi. maybe SP3 948cc?
AB 265 ok?chrisk said:
but then you start to lose me here?
why AB 260?chrisk said:
and now you say AB 256 fitted? A simple mix up? (dunno)
chrisk said:
My question is,
Have you replaced the AB 256?/265 atomizer with AB 260?
And it's worth reading your earlier 'oil leak' thread again, as there is good advice from Q and Lee in that thread, and the Piranha Brothers know far more about setting up SF twins than this bloke from da cane fields.
http://www.laverdaforum.com/forum/index.php/topic,97735.0.html
just saying 8)
Rob
Hero member
- Location
- Midlands, UK
Haven't kept up to date with latest posts but one thing springs to mind with your new DellOrto carbs. Bob Dixon was having problems with his Barcelona rep. for which he'd also bought new carbs. Turns out there are two lengths of emulsion tube... and his had the wrong length fitted. It was Gijs van Dijk who spotted that at Spa a year or four ago...
Yes, I know you're talking fluffiness off idle so may be irrelevant, and no, I can't remember the symptoms Bob was experiencing. But just a thought
Yes, I know you're talking fluffiness off idle so may be irrelevant, and no, I can't remember the symptoms Bob was experiencing. But just a thought
chrisk
Hero member
- Location
- Brisbane, Australia
Rob said:
Thanks Rob I?ll double check them.
Yes Mark, now has ab260 tubes. Bear in mind, It idles fine, and runs great above 2,500.
As Mike from Gowanlochs said, when I told him the problems, good mixture at idle, off idle shit and really lean at this stage, then good power and smooth up from 2,500.
What you have is essentially a race engine, your problem needs larger pilot jets. What happens at idle (regarding leanness or richness) is neither here nor there. That?s what we do to the Ducati race bikes.
Yep I know, this will upset idle mixture, but what he says makes sense, to me.
chrisk
Hero member
- Location
- Brisbane, Australia
New mixture screws in, set to two turns out. Won?t start hot without choke.
Better on road, opened choke a bit while riding, wow, almost perfect. The slightest hic at about 1/8 throttle but pretty smooth, all the way through. 68 pilots now, I?ll try 70?s.
Better on road, opened choke a bit while riding, wow, almost perfect. The slightest hic at about 1/8 throttle but pretty smooth, all the way through. 68 pilots now, I?ll try 70?s.
Tippie
Hero member
- Location
- Dr?bak, Norway
Carb setup is far more steered by throttle position than revs. Put marks on your grip and casting for point of cable takeup, half, and full throttle. Then ride it and you can see how much throttle you have. Half throttle (middle of needle range) on stock SF is end of the first handful.
chrisk
Hero member
- Location
- Brisbane, Australia
Okay, out with the white out.
piranha-bro2
Hero member
- Location
- Melbourne
Time to grab a std Laverda 36mm pull it apart, sus the bits, compare with what you've got and proceed from there. Too many freakin' variables!
chrisk
Hero member
- Location
- Brisbane, Australia
T & Q, So close now, it put a smile on my face .... a bit more fettling and it?s good to go. Red changed the advance curve yesterday, maybe that helped a bit.
All in all, we are heading in the right direction.
I was reading heaps of articles about people setting up carbs, the trials and tribulations are endless. My carb adventure pails into insignificance in comparison to some I read about.
Dyno guy said that my bike would be far better off with Lectron carbs.
No jets at all.
Google them, rather interesting, and tempting.
All in all, we are heading in the right direction.
I was reading heaps of articles about people setting up carbs, the trials and tribulations are endless. My carb adventure pails into insignificance in comparison to some I read about.
Dyno guy said that my bike would be far better off with Lectron carbs.
No jets at all.Google them, rather interesting, and tempting.
chrisk
Hero member
- Location
- Brisbane, Australia
rowdypat said:
Lectron carbs? http://www.lectroncarb.com.au/
had a set of Lectron carbs on my 900cc Laverda twin back in 1977/78, was running the engine on methanol at the time
got stopped by the police on my way to work one day and told to push it home, lucky for me I was only two blocks from home as they followed me
back in those days the Lectron's were mainly used for drag strip duty but that has probably changed now
got stopped by the police on my way to work one day and told to push it home, lucky for me I was only two blocks from home as they followed me
back in those days the Lectron's were mainly used for drag strip duty but that has probably changed now
Basketcase
Senior member
My old Jawa speedway Dellorto SS1 did not have any jets.
Just gulped the methanol.
Remote float bowl as well.
Just gulped the methanol.
Remote float bowl as well.
helicopterjim
Hero member
- Location
- near Lone Butte, BC, Canada
Sounds like the lawnmower I had back in the early eighties. It ran on a combination of methanol and some kind of cleaning agent I got at the lab I worked at ........ where I also acid etched the cutting blade to make it as sharp as a scalpel. Had to remove the jet completely and drill out the housing ...... plus run the motor with the cooling shroud off as it needed to run as hot as possible.
I could cut as fast as I could run ......
I could cut as fast as I could run ......
piranha-bro2
Hero member
- Location
- Melbourne
Lee was lent a pair of EI carbs (basically identical in operation to a Lectron) back in our Perth days - no amount of dyno time and setting up could achieve a better result than the std Dells. All the jetting was metered by myriad needle profiles. Just wasn't worth it in the end. Maybe those carbs are ideal for methanol. Holy shaez, Red, methanol! Did you have a nitrous tank hidden away somewhere as well?chrisk said:
I think Keihin FCRs or Red's Mikunis are what you actually need, Chris. Having said that, once you get those Dells sorted you'll have no issues. Forget the pumper ramp - just pull the plungers out and toss them. I took the entire assembly off my 36s and screwed a flat cover onto it (also creates more clearance to the frame).
I'll let you know how incredible my 39mm FCRs are once I get MINE on the road
Could be a bit of a wait ...
Tippie
Hero member
- Location
- Dr?bak, Norway
Chris, keep in mind that you have 260 needle jets, (that?ll be 2.60mm) as against the standard 265 (2.65mm), and you are looking at running it really rich on the pilots to compensate. I?d be borrowing a set of dead stock Dells to try on it, or as Q says, to do a strip and compare, try to start from a standard base.
